rtl8712: intf_priv: Replace semaphore lock with completion

The semaphore 'lock' in 'intf_priv' is used as completion,
so convert it to a struct completion type.

Signed-off-by: Binoy Jayan <[e-mail]>
Reviewed-by: Arnd Bergmann <[e-mail]>
Tested-by: Larry Finger <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rtl8712/osdep_intf.h

···
 	/* when in USB, IO is through interrupt in/out endpoints */
 	struct usb_device *udev;
 	struct urb *piorw_urb;
-	struct semaphore io_retevt;
+	struct completion io_retevt_comp;
 };
 
 int r871x_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);

drivers/staging/rtl8712/usb_ops_linux.c

···
 	pintfpriv->piorw_urb = usb_alloc_urb(0, GFP_ATOMIC);
 	if (!pintfpriv->piorw_urb)
 		return _FAIL;
-	sema_init(&(pintfpriv->io_retevt), 0);
+	init_completion(&pintfpriv->io_retevt_comp);
 	return _SUCCESS;
 }
 
···
 		else
 			padapter->bSurpriseRemoved = true;
 	}
-	up(&pintfpriv->io_retevt);
+	complete(&pintfpriv->io_retevt_comp);
 }
 
 void r8712_usb_write_mem(struct intf_hdl *pintfhdl, u32 addr, u32 cnt, u8 *wmem)
···
 			  wmem, cnt, usb_write_mem_complete,
 			  pio_queue);
 	usb_submit_urb(piorw_urb, GFP_ATOMIC);
-	_down_sema(&pintfpriv->io_retevt);
+	wait_for_completion_interruptible(&pintfpriv->io_retevt_comp);
 }
 
 static void r8712_usb_read_port_complete(struct urb *purb)